Guide
Public vs private IP addresses
Your devices have two kinds of IP address: a private one at home and a public one on the internet. Here is how they differ and how they work together.
A public IP address is reachable on the internet and unique worldwide. Your internet provider assigns one to your connection, and it is the address websites see. A private IP address only works within a local network, such as your home or office Wi-Fi, and the same private addresses are reused in countless networks.
The private address ranges
Three IPv4 ranges are reserved for private networks (by RFC 1918):
| Range | Written as | Typically used by |
|---|---|---|
| 192.168.0.0 – 192.168.255.255 | 192.168.0.0/16 | Home routers |
| 10.0.0.0 – 10.255.255.255 | 10.0.0.0/8 | Companies, some home routers |
| 172.16.0.0 – 172.31.255.255 | 172.16.0.0/12 | Companies, virtual machines |
A few other ranges are also never public:
127.0.0.1(loopback): a device talking to itself.169.254.x.x(link-local): a device that couldn’t get an address from the router gives itself one of these. Seeing it usually means a connection problem.100.64.0.0 – 100.127.255.255: shared by internet providers that put many customers behind one public address (carrier-grade NAT).- In IPv6, addresses starting with
fe80:are link-local and those starting withfdare private.
How your router connects the two
Your router has both: a private address on your home network (often 192.168.1.1) and a public address from your provider. When a device at home opens a website, the router replaces the device’s private address with its public one and remembers which device asked. When the answer comes back, it forwards it to the right device. This is called network address translation, or NAT.
A side effect is that devices at home can’t be reached directly from the internet unless you set up port forwarding on the router. That keeps unexpected connections out, although NAT is not a replacement for a firewall.
Carrier-grade NAT
Because IPv4 addresses are scarce, many mobile networks and some home providers share one public address between many customers. Your router then gets an address from the 100.64.x.x range instead of a public one. Browsing works normally, but hosting a server or a game at home, or using port forwarding, usually doesn’t. Asking the provider for a public IPv4 address, or using IPv6, solves it.
How to find each address
- Public: open the IPLookr homepage; it shows the address websites see.
- Private: look in your device’s network settings. Our guide on finding your local IP address has steps for every system.
The IP lookup tells you whether any address is public or private, and who owns the public ones.
Frequently asked questions
Is 192.168.1.1 my IP address?
It is usually the private address of your router on your home network, and the address you type to open its settings. Your devices get other addresses in the same range, and your public address on the internet is a different one again.
Why do all my devices show the same IP address on IPLookr?
Because they share your router’s public address. Inside your home each device has its own private address, but towards the internet the router uses one public address for all of them.
Is it a problem if someone knows my private IP address?
Not really. Private addresses only work inside your own network, and the same ones are used in millions of other homes. Someone outside your network can’t reach you with it.
How can I change my public IP address?
Restarting your router sometimes gets you a new address from your provider, if it uses dynamic addresses. A VPN gives websites a different address altogether. A permanent change is up to your provider.